1. Field of the Invention
The present invention relates to improvements in heat exchange radiators and more particularly but not exclusively to a connector for forming a connection between a pipe fitting and a radiator panel.
2. Description of the Prior Art
A known panel radiator for room heating comprises a pair of super-imposed preformed metal sheets having water manifolds extending lengthwise of the sheets near two opposed edge regions and transverse ducts interconnecting the manifolds. The preformed sheets are welded together by an automated welding process, usually resistance welding. The manifolds extend up to the longitudinal ends of the radiator and each end of the two manifolds is closed by a respective end plate which is manually welded in position. The end plate has a threaded hole formed therein for receiving threaded pipe fittings. A radiator of this type is referred to as a "single panel radiator with end connections".
Double panel radiators having "end connections" are also known. A double panel radiator has two panels which are fixed together in parallel spaced apart relationship and, unlike the single panel radiator described above, a recess is formed in each manifold on adjacent areas of the inner, facing surfaces of the panels. Each recess extends inwardly from the longitudinal end of the panel and a connecting web of U-shaped cross-section is welded between the two panels at the periphery of the two opposed recesses. An end plate having a threaded bore formed therein is welded to the two free edges of the connection web and the manifolds to close the end of the radiator, provide a fluid connection between the two radiator panels and form the end connection.
A double or single panel radiator having end connections of this type suffers from the disadvantage that skilled manual labor is required to fit the end plates by welding and these welds may be prone to leakage.
Another known panel radiator includes a pair of preformed metal sheets also having manifolds extending lengthwise of the sheets and transverse ducts interconnecting the manifolds. The manifolds are swaged together at the transverse edges of the sheets and the sheets are welded together by a machine along the longitudinal and transverse edges. A bore is formed in the manifold wall at a distance inset from the edge of the radiator and a connector is welded onto the radiator to surround this bore. A radiator of this type is referred to as a back connection radiator because the connection is at the back of the radiator rather than on the end.
In the known arrangement the connector is projection welded into position and this requires the provision of a back up ring, having passageways in its circumference, which is positioned inside the manifold between the front and rear walls so as to surround the bore.
Projection welding has the advantage that reliable welds are produced but has the disadvantage that it requires expensive capital equipment. In addition the back up ring is redundant once welding is completed and thus constitutes an additional expense of manufacture.
Double panel back connection radiators are also known and these include two single panel radiators which are connected together by projection welding a T-shaped connection between the manifolds of the two radiator panels at or near two of the corners of the radiator. A double panel radiator having this construction suffers from the same disadvantage of a single radiator with projection welded back connection.
In another known radiator a pair of aligned bores are formed in the manifold walls and two flanged cylindrical brass components, constituting a so-called banjo connection, are inserted into the respective bores and screw threadingly interconnected with one another. A rubber sealing ring is disposed between the flange of each component and the respective manifold wall to prevent fluid leakage. Connections of this type have the advantage that they require no welding but they have the disadvantage that being turned parts they are expensive to produce. In addition the connection is visible from the front of the radiator which is undesirable aesthetically.